Omega-cyanoperfluoroalkanoyl halides and process therefor

ABSTRACT

W-CYANOPERFLUOROALKANOYL HALIDES ARE PREPARED IN HIGH YIELD BY REACTING POLYHALOALKYL W-CYANOPERFLUOROALKANOATES IN THE PRESENCE OF A LEWIS ACID. W-CYANOPERFLUOROALKANOYL FLUORIDES, BROMIDES AND IODIDES ARE ALSO CLAIMED. THE PRODUCTS ARE USEFUL INTERMEDIATES IN THE PREPARATION OF PERFL OF PERFLUOROALKYLENETRIAZINE POLYMERS.

United States Patent 01 Patented Jan. 19, 1971 3,557,165 w-CYANOPERFLUOROALKANOYL HALIDES AND PROCESS THEREFOR Edwin Dorfmau, William E. Emerson, and Russell L. K.

Carr, Grand Island, N.Y., assiguors to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York I No Drawing. Filed Aug. 17, 1967, Ser. No. 661,242

. Int. Cl. c09r 7/00 U.S. Cl. 260-404 10 Claims ABSTRACT OF THE DISCLOSURE .w-Cyanoperfluoroalkanoyl halides are prepared in high yield by reacting polyhaloalkyl w-cyanoperfluoroalkanoates in the presence of a Lewis acid. w-Cyanoperfluoro 'ialkanoyl fluorides, bromides and iodides are also claimed.

The products are useful intermediates in the preparation of perfluoroalkylenetriazine polymers.

used by Verbanic in producing the chloric compounds' however, under some circumstances, produces the compounds in relatively low yields with other products which may or may not be of practical use. A different process was therefore sought, which is the. subject of this invention. The discovered process of this invention is also disclosed as Example 14 in the said Ser. No. 573,195/ 66.

In accordance with the present invention, w-cyanoperfluoroalkanoyl halides of the formula and X is selected from chlorine, bromine, fluorine and iodine, whereina is from lto 12, are formed when polyhaloalkyl w-cyanoperfluoroalkanoates and polyhaloaralkyl w-cyanoperfluoroalkanoates of the formula where a is as defined above and R is selected from polyhaloalkyl and polyhaloaralkyl of 1 to 25 carbon atoms with at least two hydrogen "atoms on the carbon atom adjacent. to the oxygen of the oxycarbonyl group, are decomposed in the presence of a Lewis acid, and the product is recovered preferably by distillation. Halogen R is chosen from chlorine and fluorine.

.The catalyst which have been found to be especially effective are Lewis acids which are selected from the group consisting of ferric chloride, antimony pentachloride, zirconium tetrachloride, and zinc chloride. Other Lewis acids, aluminum chloride and titanium tetrachloride, have been tested for catalytic activity for this reaction but have a much lower order of activity. Still other Lewis acids such as boron trifluoride, boron trichloride, molybdenumpentachloride, tin chlorides and metal chlorides, fluorides, bromides and iodides such as zirconium tetraiodide' and antimony bromide may have more or less activity for the catalysis of this reaction.

Sodium fluoride isnot a Lewis acid and has relatively little catalytic activity for the process of this invention.

Lewis acids of the metal halides of fluorine, bromine and iodine may be used in greater than catalytic amounts to convert the polyhaloalkyl w-cyanoperfluoroalkanoates and polyhaloaralkyl w-cyanoperfluoroalkanoates to the corresponding w-cyanoperfluoroalkanoyl fluorides, bromides and iodides in situ, that is, in one operational step, thus avoiding the recovery of w-cyanoperfluoroalkanoyl chlorides as a separate step. The w-cyanoperfluoroalkanoyl halides may also be prepared in situ in one operational step by treating the polyhaloalkyl w-cyanoperfluoroalkanoates and polyhaloaralkyl w-cyanoperfluoroalkanoates with a mixture of Lewis acid in catalytic amount, and excess metal halide where the halogen is selected from fluorine, bromine and iodine, and the metal is chosen from Groups I, II, III, IV, V, VI!) and VIII of the Periodic Table.

In the absence of a catalyst, the lower-boiling species of polyhaloalkyl w-cyanoperfluoroalkanoates and polyhaloaralkyl w-cyanoperfluoroalkanoates are distilled overhead rather than converted to the acid chlorides under the conditions of our process. I

A catalytic amount of the Lewis acid is to be used, preferably between about 1.0 to about 1-5 percent by weight.

In the above statement of the invention R is polyhaloalkyl or polyhaloaralkyl of from 1 to 25 carbon atoms with at least two halogen atoms on the carbon atom ad jacent to the oxygen in the oxycarbonyl group. Illustrative of such groups are: trichloromethyl, dichloromethyl, polychloroethyl, pentachloroethyl, tetrachloroethyl, dichlorotrifluoroethyl, and dichlorobenzyl, and the like.

Thus, where R is trichloromethyl and x is 3, then the starting material is trichloromethyl w-cyanoperfiuorobutyrate; when x is 2, trichloromethyl w-cyanoperfluoropropionate; when x is 6, trichloromethyl w-cyanoperfluoroheptanoate, and when x is 8, trichloromethyl wcyanoperfluorononanoate. Also, when R is tetrachloroethyl and x is 3, then the starting material is tetrachloroethyl w-cyanoperfluorobutyrate, and when x is 6, tetrachloroethyl w-cyanoperfluoropheptanoate, etc.

A preferred R group is trichloromethyl which is economical to prepare and which gives carbonyl chloride as a by-product. Higher molecular weight groups such as dichloroperfiuoroalkyl groups of 6 to 14 carbon atoms would also be desirable in the synthesis of lower members of the series for these would give by-product acid chlorides which would be easily separated by distillation.

The polyhaloalkyl w-cyanoperfluoroalkanoate and polyhaloaralkyl w-cyanoperfluoroalkanoate starting materials for the process of this invention are prepared by photochlorination of the corresponding alkyl w-cyanoperfiuoroalkanoates and aralkyl w-cyanoperfluoroalkanoates, described in copending application Ser. No. 661,180 filed Aug. 17, 1967.

The corresponding alkyl w-cyanoperfluoroalkanoates and aralkyl 'w-cyanoperfluoroalkanoates are produced by treatment with P 0 of the corresponding perfluoroalkyleneamidate in accordance with Equation 1:

CNH CN Q: 2 5 2):

(10R COR 0 l where R is alkyl or aralkyl of 1 to 25 carbon atoms, and x is as defined above. This is described in copending application Ser. No. 661,241, filed Aug. 17, 1967.

The amidate is produced either by (a) treatment with ammonia of a perfluorinated dicar-boxylic acid ester of the formula it o R (C F2) x IC 0 R1 (l where x and R are as defined above, or (b) by treatment with an alcohol of the imide of the perfluorodicarboxylic acid, in accordance with Equation II:

(II) 0 H g /CNII (C F5; NH R OII (C1 2):

\ COR where x and R are defined as above. This is described in copending application Ser. No. 661,240, filed Aug. 17, 1967. The diesters and imides are known compositions. An example of a dialkyl perfluoroalkylene dicarboxylic is dimethyl perfluoroglutarate which was prepared by A. L. Henne and W. J. Zimmerscheid, I. Am. Chem. Soc., 67, 1235 (1945). Another example is dimethyl perfluorosebacate which was prepared by treatment of perfluorosebacoyl chloride with methanol, and recovering the diester by vacuum distillation: B.P. 120-122 at 4 mm. Perfluorosebacoyl chloride, B.P. 1157 at 36 mm., was prepared from the acid in 86% yield using a fourfold quantity of thionyl chloride, ethyl acetate as solvent, and a catalytic amount of pyridine. Perfluorosebacic acid and perfluorotetradecanedioic acid are known compounds described by I. L. Knunyants et al., Proc. Acad. Sci. U.S.S.R., 129, 328 (1959) and I. L. Knunyants and M. N. Krasuskaya, Bull. Acad. Sci. U.S.S.R., 1963, 190. Dipropyl perfluorosebacate was prepared from perfluorosebacic acid, n-propyl alcohol and a catalytic amount of sulfuric acid. The by-product water of reaction was re moved by distillation of the propyl alcohol-water azeotropic mixture. The dipropyl perfiuorosebacate had a boiling point of 125128 centigrade at 5 millimeters of mercury pressure (absolute). Diethyl difiuoromalonate or dimethyl difiuoromalonate may be produced by the method of C. E. Inman, R. E. Oesterling, and E. S. Tyczkowski, J. Am. Chem. Soc., 80, 6533-5 (1958). Perfluoropimelic acid, perfluoroazelaic acid and perfiuorononanedioic acid may be made by electrolytic fluorination of the corresponding hydrocarbon acids by the method of Guenther, U.S. Pat. 2,606,206, which gave perfiuorosebacic acid. The esters of these acids can be made by the procedures used for the preparation of the perfiuorosebacic acid esters described above. Examples of imides are perfluorosuccinimide and perfluoroglutarimide, which were prepared by the method of A. L. Henne and W. F. Zimmer, J. Am. Chem. Soc., 73, 1103 (1951). Other homolgous perfluoroalkanedioic acid imides may be prepared by this process when the corresponding perfluoroalkanedioic acid amides are used as starting materials.

The reaction is carried out at relatively low temperature of between about 100 degrees Centigrade to about 200 degrees centigrade, with a preferred range being between about 140 and about 180 degrees centigrade. Above about 200 degrees centigrade side reactions involving the nitrile group may occur. Below about 100 degrees Centigrade the reaction is relatively slow.

In the absence of a catalyst the reaction is too slow and the result is to distill the more volatile polyhaloalkyl w-cyanoperfluoroalkanoates, rather than decompose them to the corresponding acid chlorides.

The reaction of this invention can be conducted under atmospheric pressure. However, pressures above and below atmospheric pressure may also be used.

Where the product is recovered from the reaction mixture by distillation, the pressure to be used depends on the boiling point of the product. That is, where the atmospheric boiling point of the product is above the reaction temperature range, then vacuum may be applied in order to recover the product at a lower temperature.-

A crude product may be distilled over and then further purified such as by redistillation.

Anhydrous conditions are to be maintained during the reaction to avoid formation of thehydrolysis products of the polyhaloalkyl w-cyanoperfluoroalkanoates and of the w-cyanoperfluoroalkanoyl chlorides.

An inert solvent may be used which may lower the reaction temperature; however, it is not necessary.

The process of this invention not only includes recovery of the product as the acid chloride, but also embraces the corresponding acid fluorides, acid bromides and acid iodldes, which can be produced by a subsequent halogen exchange reaction using metal halides where the halogen is selected from bromine, fluorine and iodine, and the metal is chosen from Groups I, II, III, IV, V, VIb and VIII of the Periodic Table. Examples of such metal salts are potassium hydrogen fluoride (KHF potassium fluoride, calcium bromide, aluminum bromide, silicon bromide, zirconium tetraiodide, antimony bromide, molybdenum hexafluoride, ferric bromide, ferric iodide and the like.

Thus the compositions claimed by this invention are defined by the formula:

where a is from 1 to 12 and X is selected from fluorine, bromine and iodine. A preferred subclass of compound in this class of compounds is where X is fluorine.

The cyanoperfluoroalkanoyl chlorides may be used to prepare the corresponding cyanoperfluoroalkanoyl fluorides, cyanoperfluoroalkanoyl bromides, and cyanoperfluoroalkanoyl iodides. Thus, it has been found that when the acid chloride is heated and stirred with potassium bifiuoride, the acid fluoride is formed and may be recovered by fractional distillation. A polar solvent and other metal fluorides may also be used for the halogen exchange reaction.

To make the acid bromides and acid iodides a similar halogen exchange reaction may be used which employs bromide and iodide salts and the cyanoperfluoroalkanoyl chloride. The cyanoperfluoroalkanoyl iodides may be prepared by heating the acid chloride with anhydrous calcium iodide. The cyanoperfluoroalkanoyl bromides may be prepared by heating the acid chloride with excess finely divided anhydrous calcium bromide.

The cyanoperfluoroalkanoyl fluorides are useful as intermediates for photodecomposition reactions where ultraviolet radiation below 2400 Angstrom units is used, which would give perfluoroalkane dinitriles. The cyanoperfluoroalkanoyl chlorides, bromides, and iodides would give a larger amount of the corresponding cyanoperfluoroalkyl chlorides, bromides, and iodides, and substantially less of the perfluoroalkane dinitriles. This may be due to the more facile cleavage of the carbon-chlorine, carbon-bromine, and carbon-iodine chemical bond by photoactivation as compared to that of the carbon-fluorine bond.

Thus, compounds produced by the process of this invention are:

cyanodifluoroacetyl chloride, when x=1 w-cyanotetrafluoropropionyl chloride, when x=2 w-cyanohexafluorobutryl chloride, when x=3 w-cyanooctafluorovaleryl chloride, when x=4 w-cyanodecafluorohexanoyl chloride, when x=5 w-cyanododecafiuoroheptanoyl chloride, when x:6 w-cyanotetradecafiuorooctanoyl chloride, when x=7 w-cyanohexadecafluorononanoyl chloride, when x=8 w'-cyanooctadecafluorodecanoyl chloride, when x=9 w-cyanoperfluoroundecanoyl chloride, when x=10 w-cyanoperfluorododecanoyl chloride, when x=ll w-cyanoperfiuorotridecanoyl chloride,when x=12 w-cyanohexafluorobutryl fluoride, when x=3 w-cyanohexafluorobutyryl bromide, when x=3 tq-cyanooctafluorovaleryl bromide, when x=4 d-eyanohexafluorobutryl iodide, when x=3 w-cyanooctafluorovaleryl iodide, when x=4 a-cyanodifiuoroacetyl fluoride, when x =l w-cyanotetrafluoropropionyl fluoride, when x=2 w-cyanooctafluorovaleryl fluoride, when x=4 w-cyanodecafiuorohexanonyl fluoride, whenx=5 ai-cyanododecafluoroheptanoyl fluoride, when x=6 i i-cyariotetradec'afluorooctanoyl fluoride, when x=7 -cy anohexadecafluorononanoyl fluoride, when x=8 iqcyanooctadecafluorodecanoyl fluoride, when x=9 qa-cyanofluoroundecanoyl fluoride, when x: 10 w -c yanoperfluorododecanoyl fluoride, when x: 11 v;cyan'operfluorotridecanoyl fluoride, when x=12 and-the like.

By this process, at the same'time a second product is also prepared such as phosgene when R is trichloromethyl. The cyanoperfluoroalkanoyl halides produced by the process of this invention are useful in the preparation of perfluoroalkylenetriazine polymers, such as those disclosed in copendingapplication-Ser. No. 533,430, filed Mar. 11, 1966. Thesepolymers' are thermally stable and resistant to some solvents, while being'solublein other solvents, such as "alkyl" acetates, alkyl perfluoroalkanoates, and flu'orin'ated solvents such as fluorinated xylenesand fluorinecontaining triazines. The cyanoperfluoroalkanoyl halides may also be treated with pe'rflu or'inated carboxylic acids to evolve hydrogen halides "and to produce mixed perfluorinated carboxylic a'nhydrides. These mixed anhydrides may also be used to prepare perfluoroalkylenetriazine polymers of application -Ser. No..-533,430 andthus represent an economical method of recovering the by-product acids which are formed in the polymerization process of application Ser. No. 533,430. illustrative-mixed anhydrides of this .type are th'e following:

and

nowrnn iot iogry invention is further illustratedin examples below, wherein temperatures are in-degrees centigrade and parts are'by weight. 5

" EXAMPLE 1 'w-Cyanoperfluorononanoyl chloride 7 v Trichl'or omethyl w cyanoperfluorononanoate. (25.1

grams), and ferric chloride (3 grams) wereheatedin a distilling apparatus to 140 degrees centigrade in 2 hours, andv then to 16.0.degrees centigrade in 1.5 hours. A vacuum (52 millimeters-mercury) was then applied and the distillate was collected in cuts: .Cut 1,- 15.6 grams, boiling point 99-102 degrees centigrade, 89.5 percent pure by gas liquid chromatographic analysis; and Cut 2, 3.0 grams, boilingupoint. 102-1l-0 degrees centigrade, 92.2 percent pure bygas liquid chromatographic analysis.

Analysis-Calculated for C Cl NO (percent) C,

24.53; F, 62.10; N,2.86..Found (percent): .C, 24.72; H,

0.00;\N,-3;10; yield 79%.

The. infrared spectrum, was characteristic fornitrile and acid chloride with bands at 2250 and 1800 reciprocal centimeters, respectively.

In a similar manner, by substituting trichloromethyl w-cyanododecafluoroheptanoate (20.8 grams) for the trichloromethyl w-cyanohexadecafiuorononanoate used in the above reaction. w-cyanododecafluoroheptanoyl chloride is obtained.

-In a similar manner, by substituting trichloromethyl w-cyanooctafluoropentanoate (16.5 grams) for the trichloromethyl w-cyanohexadecafluorononanoate used in the above reaction, w-cyanooctafluoropentanoyl chloride can be obtained.

EXAMPLE 2 w-Cyanoperfluorobutryl chloride Trichloromethyl w-cyanoperfluorobutyrate, (577 parts), and ferric chloride (10.5 parts), were heated in distillation equipment at to degrees centigrade. Carbonyl chloride and w-cyanoperfluorobutryl chloride (300 parts) were collected. The crude product was fractionated using a helix-packed column to yield w-cyanoperfluorobutryl chloride (264 parts), with a boiling point of 74- 75.5 degrees centrigrade.

Analysis.Calculated for C ClF NO (percent): C, 25.07; Cl, 14.80; F, 47.60; N, 5.85. Found (percent): C, 25.15; H, 0.00; N, 5.58.

The infrared spectrum was identical with that obtained from a sample which was made by the reaction of perfluoroglutaramide with benzoyl chloride which is described in the said Verbanic patent application.

In a similar manner, by substituting trichloromethyl w-cyanotetrafluoropropionate (492 grams) for the trichloromethyl w-cyanoperfluorobutyrate used in Example2, w-cyanotetrafluoropropionyl chloride can be obtained.

In a similar manner, by substituting trichloromethyl w-cyanodifluoroacetate (406 grams) for the trichloro-' methyl w-cyanoperfluorobutyrate used in Example 2, cyanodifluoracetyl chloride can be obtained.

- EXAMPLE 3 w-Cyanoperfluorobutyryl chloride from dichloromethyl w-cyanoperfluorobutyrate w-Cyanoperfluorobutyryl chloride-ferric chloride catalyst Trichl'oromethyl w-cyanoperfluorobutyrate' (22 parts), and ferric chloride (1 part),'were combinedina distillation apparatus and heated in any oil bath at degrees centigrade. w-Cyanoperfluorobutyryl chloride (11 parts), was collected in the distillate. A distillation residue of 3 parts containing higher boiling materials was also obtained.

Incomparison with Example ,10 belowit can be seen that ferric. chloride catalysis gives a much higher yield of'w-cyanoperfluoroalkanoyl chloride and at a lower .reaction temperature than anon-Lewis acid material such as sodium fluoride.

EXAMPLE 5 v w-Cyanoperfluorobutyryl chloride-aluminum chloride catalyst j 'f "I Trichloromethyl w-cyanoperfluorobutyrate, (22 parts), and aluminum chloride ,(1 part-) were. combined ina distillation apparatus and heated in an oil bath at 150 degrees centigrade. 'A distillate (1.6 parts), was obtained which contained 1% of w-cyanoperfluorobutyryl chloride.

EXAMPLES Trichloromethyl w-cyanoperfluorobutyrate (22 parts),

and titanium chloride (1 part), were combined in a distillation apparatus and heated in an oil bath at 180 degrees centigrade. The distillate was 4.2 parts, containing 1% of w-cyanoperfiuorobutyryl chloride but was essentially trichloromethyl w-cyanoperfluorobutyrate.

EXAMPLE 7 w-Cyanoperfluorobutyryl chloride-zinc chloride catalyst Trichloromethyl w-cyanoperfiuorobutyrate (22 parts), and zinc chloride (1 part), were combined in a distillation apparatus and heated in an oil bath at 180 degrees centigrade. w-Cyanoperfluorobutyryl chloride (11.2 parts), was collected in the distillate.

EXAMPLE 8 w-Cyanoperfluorobutyryl chloride-zirconium chloride catalyst Trichloromethyl w-cyanoperfiuorobutyrate (22 parts), and zirconium chloride (1 part), were combined in a distillation apparatus and heated in an oil bath at 150 to 178 degrees centigrade. The distillate was 7.6 parts containing 72% of w-cyanoperfluorobutyryl chloride.

EXAMPLE 9 w-Cyanoperfluorobutyryl chloride-antimony pentachloride catalyst Trichloromethyl w-cyanoperfluorobutyrate (22 parts), and antimony pentachloride (1 part), were combined in a distillation apparatus and heated in an oil bath at 140 to 150 degrees centigrade. w-Cyanoperfiuorobutyryl chloride (9.2 parts), was obtained in the distillate.

EXAMPLE 10 w-Cyanoperlluorobutyryl chloride-sodium fluoride catalyst Trichloromethyl w-cyanoperfiuorobutyrate (10 parts), and sodium fluoride (1 part), were combined in a distillation apparatus and heated in an oil bath. The temperature of the bath was slowly increased but no reaction occurred until the temperature reached 190 degrees centigrade. w-Cyanoperfiuorobutyryl chloride (1.2 grams), was collected at a reaction temperature of 190 to 210 degrees centigrade.

EXAMPLE 11 w-Cyanoperfluorobutyryl chloride from tetrachloroethyl w-cyanoperfiuorobutyrates A mixture of tetrachloroethyl w-cyanoperfluorobutyrates (40 parts), and ferric chloride parts), were combined in a distillation apparatus and heated in an oil bath at 150 to 180 degrees centigrade. The distillate (14 parts), contained 45% of w-cyanoperfiuorobutyryl chloride.

Preparation of polyhaloalkyl w-cyanoperfluoroalkanoate 1 starting materials In accordance with Ser. No. 661,180, filed Aug. 17, 1967, the starting materials are prepared in the following illustrative manner.

EXAMPLE 12 Trichloromethyl w-cyanohexafiuorobutyrate Methyl 4-cyanoperfluorobutyrate, 39.0 grams, was treated with chlorine gas in a 3-necked round bottomed flask with stirring at 50-70 degrees centigrade. Distillation at 26-34 degrees centigrade and 0.10 mm. mercury, gave 20.5 grams of distillate.

Analysis.--Calculated for C Cl F NO, (percent): C, 20.68; Cl, 30.53; N, 4.02. Found (percent): C, 21.47; Cl, 31.28; N, 4.28.

In a similar manner, by substituting methyl w-cyanotetrafluoropropionate (30.7 grams) for the methyl wcyanoperfiuorobutyrate used in the above reaction, trichloromethyl w-cyanotetrafluoropropionate can be obtained.

In a similar manner, by substituting methyl w-cyanodifluoroacetate (22.4 grams) for the methyl w-cyanoperfluorobutyrate used in the above reaction, trichloromethyl w-cyanodifiuoroacetate can be obtained.

Preparation of alkyl w-cyanoperfluoroalkanoate and aralkyl w-cyanoperfluoroalkanoate starting materials In accordance with Ser. No. 661,241, filed Aug. 17, 1967, the derivative starting materials are prepared in the following illustrative manner.

EXAMPLE 13 Methyl w-cyanohexadecafiuorononanoate A mixture of methyl perfluorosebacamidate (61 grams) and phosphorus pentoxide (185 grams) was heated in a bath maintained at about 200 degrees centigrade. After 15 minutes the pressure was reduced to 35 millimeters mercury to permit distillation of the product. Distillate (50.5 grams) boiling at 111-113 degrees centigrade was collected during the next two hours. The distillate was redistilled at 35 millimeters to give a fraction (39 grams) boiling at 112 to 115 degrees centigrade.

Analysis-Calculated for C I-I F NO (percent): C, 27.23; H, 0.62; N, 2.89. Found ,(percent): C, 27.14; H, 0.87; N, 2.91.

In a similar manner, by substituting methyl perfluorosuberamidate (48.8 grams) for the methyl perfluorosebacamidate used in the above reaction, methyl w-cyanododecafiuoroheptanoate can be obtained.

In a similar manner, by substituting methyl perfiuoroadipamidate (36.7 grams) for the methyl per fl-uorosebacamidate used in the above reaction, methyl w-cyanooctafiuoropentanoate can be obtained.

In a similar manner, by substituting n-propyl periluorosebacamidate (64.4 grams) for the methyl perfiuorosebacamidate used in the above reaction, n-propyl wcyanohexadecafiuorononanoate can be obtained.

Preparation of perfiuoroamidate starting materials from diester In accordance with Ser. No. 661,240, filed Aug. 17, 1967, the derivative starting materials are prepared from the diester in the following illustrative manner.

EXAMPLE 14 Methyl perfluorosebacamidate To dimethyl perfiuorosebacate (252 grams, 0.48 mole), in methylene chloride (700 milliliters), was added ammonia (5.8 grams, 0.34 mole), at between about 25 to about 29 degrees centigrade. The mixture was stirred for 7 hours. Cooled methyl perfiuorosebacamidate grams) was obtained at 100 degrees centigrade at 0.25 millimeter mercury. This product was recrystallized from toluene which gave white crystals (61 grams) with a melting point of between and 116 degrees centigrade.

Analysis.Calculated for C H F NO (percent): C, 26.26; H, 1.00; N, 2.78. Found (percent): C, 26.13; H, 1.06; N, 2.84.

In a similar manner by substituting dimethyl perfiuorosuberate (201 grams, 0.48 mole), for the dimethyl perfiuorosebacate used in the above reaction, methyl perfluoroseberamidate can be obtained.

In a similar manner, by substituting methyl difluoromalonate (81 grams, 0.48 mole), for the dimethyl perfluorosebacate used in the above reaction, methyl difluoromalonamidate can be obtained.

In a similar manner, by substituting methyl perfiuoroadipate (152.5 grams, 0.48 mole), for the dimethyl perfiuorosebacate used in the above reaction, methyl perfiuoroadipamidate can be obtained.

Preparation of perfiuoroamidate starting materials from the imide In accordance with Ser. No. 661,240, filed Aug. 17,

EXAMPLE 1s Methyl perfluoroglutaramidate I Perfluoroglutarimide,(5 grams, 0.023 mole) .and-met-hanol (0.79 gram, 0.0246 mole), were sealed in a..=t ube and heatedto about 100 degrees.centigradeaInSO minufesithe reaction was almost complete as indicated by infrared analysis. Heating was. continued f,or, abou t,.- 9Q-: minutes more to complete the reaction. A solid productwas re; crystallized from toluene .anddried. It had a melting point of 45.045.5 degrees centigrade.

Analysis.Calculated for C H F NO5 (percent): C, 28.47; H, 1.99; N, 5.53. Found (percent): C,"28;40; H, 1.99; N, 5.62.

In a similar manner; by substituting perfluorostgccinimide (3.93 grams, 0.023- mole for the 'perfluoroglu'tarimide used in the above rreact ion rnethyl perfluorosuccinamidate can be obtained.

EXAMPLE 1'6 Preparation of 4-cyanoperfiubrobutyrylfluo ride a A mixture of 4-cyanoperfluorobutyryl chloride ,(49 grams, 0.204 mole), and anhydrous KHF "('17 grams; 0.218 mole), was heated with stirring-under nitrogen to 118 degrees centigrade. w-Cyanohexafluorobutyryl fluoride distilled from the mixture as it was formed, and 25 grams were isolated with a boiling point offlfi-45-rde'grees centigrade, in a 54.7 percent yield.

In a similar manner, by substituting w-cyanoperfluorovaleryl chloride (59.2 grams) for the w-cyanoperfll'iorobutyryl chloride used in the above reaction, w-cyanoperfiuorovale ryl fluoride can be obtained.

In a similar manner, by substituting w-cyanoperfluoroheptanoyl chloride (79.5 grams) for the w-cyanoperfiuorobutyryl chloride used in the above reaction, w-cyanoperfluoroheptanoyl fluoride can be obtained. ,1

In a similar manner, by substituting w-cyanoperfiuprononanoyl chloride (100 grams) for the w-cyanoperfiuprobutyryl chloride used in the above reaction, w-cyanoperfluorononanoyl fluoride can be obtained.

In the manner after Example 16 where the acid bromide is desired, 4-cyanoperfluorobutyryl chloride is treated with excess finely divided, anhydrous calcium bromide and the 4-cyanoperfluorobutyryl bromide is recovered by distillation.

In a manner after Example 16 where the acid iodide is desired, 4-cyanoperfluorobutyryl chloride is treated gtvith excess finely divided anhydrous calcium iodide, and the 4-cyanoperfluorobutyryl iodide is then recovered by distillation. "F

Although this invention has been illustrated by citing specific details of given species embraced within the scope of the invention, it is to be understood that various modifications Within the invention are possible, some of which have been referred to above.

For instance, w-cyanoperfluoroetheralkanoyl halides may be made. These compounds have the formulae:

ll Nowmmrloorox and where s is an integer of from 0 to 12, X is selected from the group consisting of chlorine, bromine, iodine, and

10 fluorine, and Z is selected from the group consisting'of fluorine. and trifluoromethyl (CB where p is an integer of from 2 to 12, and X and Z are as defined above,

No oraromowror o orri x and uoomoorlt lm oomomhox where y is an integer of from 0 to 100, and s, X and Z are as defined above,

whereXis as definedabove. Illustrative compounds embraced by this'jpro'ces's are:

H NC 0 F2)40 CF20 c1 H NC 0 F20 0 F950 0 F2001 ll NC 0 F20 F20 C F2C F20 Cl and II NCCFzCFzOCFzCFgCBI Other compounds embraced by this process are -cyanoperfluoroalkanoyl halides of branched perfiuoroalkanedioic acids such as the following examples:

0 NCCFgC FzcFcFg cl and 1 1 What is claimed is: 1. A process for the preparation of omega cyano perfiuoroalkanoyl halides of the formula about 100 centigrade to about 200 centigrade in the presence of a Lewis acid as a compound of the formula CN (01 g.

fion

where R is selected from the group consisting of polyhalo lower alkyl and polyhalo benzyl wherein said polyhalo has at least 2 chlorine atoms on the carbon atom adjacent the oxygen inthe oxycarbonyl group, and the halogen is selected from the group consisting of chlorine and fluorine, and recovering the product so produced.

2. The process of claim 1 wherein the Lewis acid is ferric chloride.

3. The compound of claim 1 wherein the Lewis acid is zinc chloride.

4. The process of claim 1 wherein the Lewis acid is "zirconium tetrachloride.

5. The process of claim 1 wherein the Lewis acid is antimony pentachloride.

6. The process of claim 1 wherein R is trichloromethyl and a is 3.

7. The process of claim 1 wherein R is tr'ichloromethyl and a is 4;

8. The process of claim 1 wherein R is trichloromethyl and a is 8. r

9. The process of claim 1 wherein R is tetrachloroethyl and q is 3.

10. The process of claim 1 wherein R is trichloromethyl and a is 6.

References Cited UNITED STATES PATENTS 3,274,229 9/1966 Verbanic 260465 2,865,959 12/1958 Toland 26()-544 3,047,610 7/1962 Brace et a1. 260-544 3,349,105 lO/l967 Verbanic 260=404 OTHER REFERENCES Naturwissenschaften, Ober den Protoenangrifl Bei der Saueren Esterhydrolyse, vol. 42, p. 461 (1955).,

Krauss et al.: Proton Attack in Acid Ester Hydrolysis, CA 51, p. 4804 (1957). 

